A fellow hacker is challenging you to exploit a simple python script.
To exploit it live, you have to create your Warchall account and try your luck there.
To see what it is about you can also view the source here.

Note: It is not required to trigger a race condition, but it should work as well.
Note: You have to use the binary "pytong" not the pytong.py. It is a wrapper which is needed for SETREGID and finally gives the solution.